The components of a generator of a wind turbine are subjected to strong mechanical loads, which can bring about damage to the generator components. If these damaged generator components are not exchanged, consequential damage may occur, involving high costs to repair. It is therefore necessary to find out about damaged generator components as early as possible, in order to exchange them before sequential damage occurs. The damaged generator components cause vibrations, which are manifested by fluctuations in the rotational speed of the generator. These vibrations can be sensed for example at the generator bearings.
Known wind turbine diagnostic devices comprise vibration sensors at the generator bearings. Owing to the restricted possibilities for positioning the vibration sensors on the generator bearings, these sensors primarily sense radial vibrations. Axial vibrations are sensed only partially or not at all. Consequently, known vibration sensors only offer limited possibilities for diagnosis with respect to mechanical damage caused by axial vibrations.